block: Block layer data integrity support

Some block devices support verifying the integrity of requests by way
of checksums or other protection information that is submitted along
with the I/O.

This patch implements support for generating and verifying integrity
metadata, as well as correctly merging, splitting and cloning bios and
requests that have this extra information attached.

See Documentation/block/data-integrity.txt for more information.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 29 insertions, 3 deletions

diff --git a/fs/bio.c b/fs/bio.c
index 7a6598abc967..7761c84c7032 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -50,6 +50,11 @@ static struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = {
  */
 struct bio_set *fs_bio_set;
 
+unsigned int bvec_nr_vecs(unsigned short idx)
+{
+        return bvec_slabs[idx].nr_vecs;
+}
+
 struct bio_vec *bvec_alloc_bs(gfp_t gfp_mask, int nr, unsigned long *idx, struct bio_set *bs)
 {
         struct bio_vec *bvl;
@@ -91,6 +96,9 @@ void bio_free(struct bio *bio, struct bio_set *bio_set)
                 mempool_free(bio->bi_io_vec, bio_set->bvec_pools[pool_idx]);
         }
 
+        if (bio_integrity(bio))
+                bio_integrity_free(bio, bio_set);
+
         mempool_free(bio, bio_set->bio_pool);
 }
 
@@ -249,9 +257,19 @@ struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
 {
         struct bio *b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, fs_bio_set);
 
-        if (b) {
-                b->bi_destructor = bio_fs_destructor;
-                __bio_clone(b, bio);
+        if (!b)
+                return NULL;
+
+        b->bi_destructor = bio_fs_destructor;
+        __bio_clone(b, bio);
+
+        if (bio_integrity(bio)) {
+                int ret;
+
+                ret = bio_integrity_clone(b, bio, fs_bio_set);
+
+                if (ret < 0)
+                        return NULL;
         }
 
         return b;
@@ -1223,6 +1241,9 @@ struct bio_pair *bio_split(struct bio *bi, mempool_t *pool, int first_sectors)
         bp->bio1.bi_private = bi;
         bp->bio2.bi_private = pool;
 
+        if (bio_integrity(bi))
+                bio_integrity_split(bi, bp, first_sectors);
+
         return bp;
 }
 
@@ -1264,6 +1285,7 @@ void bioset_free(struct bio_set *bs)
         if (bs->bio_pool)
                 mempool_destroy(bs->bio_pool);
 
+        bioset_integrity_free(bs);
         biovec_free_pools(bs);
 
         kfree(bs);
@@ -1280,6 +1302,9 @@ struct bio_set *bioset_create(int bio_pool_size, int bvec_pool_size)
         if (!bs->bio_pool)
                 goto bad;
 
+        if (bioset_integrity_create(bs, bio_pool_size))
+                goto bad;
+
         if (!biovec_create_pools(bs, bvec_pool_size))
                 return bs;
 
@@ -1306,6 +1331,7 @@ static int __init init_bio(void)
 {
         bio_slab = KMEM_CACHE(bio, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
 
+        bio_integrity_init_slab();
         biovec_init_slabs();
 
         fs_bio_set = bioset_create(BIO_POOL_SIZE, 2);